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Geological-Geochemical Characters and Metallogenic Prediction of Wenquan Molybdenum Deposit in the West Qinling Area

Author: HanHaiTao
Tutor: LiuJiShun
School: Central South University
Course: Mineral prospecting and exploration
Keywords: Porphyry molybdenum deposit West Qinling Geochemical characteristics Prospecting indicators Metallogenic prediction
CLC: P618.51
Type: PhD thesis
Year: 2009
Downloads: 441
Quote: 4
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Abstract

Springs molybdenum mine located in Wushan County, Gansu Province, the Onsen territory, the Department of Gansu Nonferrous Geological Prospecting Bureau in 2000 found a large prospects porphyry molybdenum deposit. The deposit for the study, regional metallogeny and prospecting systems engineering, granite geochemistry and mineralization entry point, the main line to the magma - structure - fluid - metallogenic study mineralization geological conditions, geological features, geochemical characteristics and metallogenic mechanism and metallogenic regularity establish metallogenic model to carry out the mineralization forecast. Major achievement and understanding as follows: 1, past geological work indicates that molybdenum ore resources in the Central Orogenic Belt (Dabie - Qinling - Qilian - Kunlun), related to the granitic rocks and forming molybdenum deposits are limited to the East Qinling region constitute accounting for about 52% of the national total molybdenum reserves porphyry molybdenum belt system after the world's second largest molybdenum belt in the western United States, Climax-Henderson. However, the 2000 discovery of the hot springs molybdenum mine, breaking the pattern of distribution of the Qinling molybdenum belt, and not only its westward extension of the more than 400 km and molybdenum mine to find clear direction for the entire central orogenic belt. 2, Spa molybdenum mineral Wenquan granite base, controlled by Chenjia Dawan fine-grained biotite monzogranite porphyry strains of internal and external contacts with its fractured system, the Department of porphyry molybdenum deposit mineralization. The end of June 2007 Chenjia the Greater Bay 15 lines to 32 lines (0.3km ^{2 ), detailed survey work, the amount of molybdenum ore exploration was 7805WT (0.053 × 10 ^{-2 ). The peripheral 260km ^{2 Spa rock body is still found 42 molybdenum mine (of) points, showing a large molybdenum mine exploration potential. 3, Spa granite base is chiefly tablets like porphyritic monzogranite intruded into the lower greenschist facies volcanic Lower Proterozoic Qinling Group greenschist facies volcanic - sedimentary metamorphic rocks and lower Paleozoic Liziyuan Group - sedimentary metamorphic series and in the Upper Devonian Liba group - Dacaotan Group carbonate rocks, sandstone and shale. And controlled by the Baoji to Tianshui ~ the Linxia fault zone (south side) and insidious the Wudu to-day water depth the fracture (west) junction site. Spa molybdenum mine the ore-bearing rock Department Springs batholith the complement - the Chenjia Big Bay porphyry strains of emplacement little later in Hot Springs batholith. Mineralization age of 214 ± 7.1Ma, about Mesozoic Triassic in the period of Indo-China movement. 4, by engineering control 34 orebody single ore body is 50 to 650 m in length, thickness 5 ~ 24.4m, top depth of 38.5 5 16.5m. Mineralization type fracture zone altered rock type, micro-fractured quartz vein - stockwork-type and disseminated type. Fine veins intensive at that constitute the orebody, it is unclear boundaries of the ore body and surrounding rock, the need for chemical analysis before being delineated. The ore is mainly composed of molybdenite, quartz and minor pyrite, chalcopyrite, flash blende, scheelite, arsenopyrite, tetrahedrite, galena, bornite, feldspar and mica, etc.. Wall rock alteration potassium silicide, silicide, zeolite, red mud and other green plate rocks are not developed. 5, the mineralized porphyry SiO ₂ 71.21%, K ₂ O4.91%, K ₂ O the of Na ₂ O 8.22%, and K ₂ O greater than of Na ₂ O Rittmann rock series index (σ) average 2.45, belonging to K-rich (alkali) calc-alkaline rock series. These characteristics and molybdenum porphyry (SiO ₂ 70% ~ 77%, K ₂ O Na ₂ O8% ~ 9%, and K ₂ O is greater than that of Na ₂ O) characteristics are very similar, and its molybdenum mineralization potential. Vickers values ??compared with granite, the mineralized porphyry Mo, Cu, As, Ag element is significantly enriched, Bi, Hg, Ba, Au element losses, Pb, Zn, Sb, Co, Ni, Cr, V elements generally quite Vickers value. Mo average content of up to 45 × 10 ^{-6 Cu up to 142 × 10 ^{-6 , that ore spot magma as molybdenum mineralization material sources. 6 medium-grained porphyritic monzogranite, fine-grained biotite monzogranite porphyry total rare earth ΣREE to 126 × 10 ^{-6 and 148 × 10 ^{-6 the highest total rare earths; dark inclusions, up to 167 × 10 ^{-6 ; the quartz vein only 26.8 x 10 ^{-6 . This indicates that the first three comagmatic evolutionary product, a far cry from the quartz veins and the first three of total rare earth, should account for the late hydrothermal product was 4.5 to 5.6; LREE / HREE (La / Sm) _N about 4.6 (Gd / Yb) _N to 1.97 to 2.53 to 15.13 to 24.06, (La / Yb) _N, δEu value of 0.66 ~ 0.68, δCe 0.83 to 0.90, the above data show that: LREE and HREE fractionation significantly lower level, granite, quartz veins, dark inclusions of rare earth elements has homology shows crustal remelting renewable granitic magma The mantle juice mixed characteristics. This is also consistent with the micro-fine grained mafic enclaves and mafic dykes symbiosis. 7, the the granitic magma intrusion role is the dynamic mechanism of the formation of major ore-bearing fracture, the the formation fracture zones and JOINTED system as the main host structures. The genesis model: role of Indosinian intracontinental plate mantle fluid the Precambrian basement remelting formed granitic magma, large fault zone along the Baoji to day water depth insidious Wudu to Tianshui fracture The massive alien with node Activities Wenquan granite base. With the magma intrusion and evolution of invasive the porphyry strains to Chenjia large Bay formation is rich in minerals of high pressure fluid phase. These high-pressure fluid phase, opening up the access on their own or hydraulic fracturing, or form the pulse rate of the high content and high permeability zones along the the favorable channel fault structure increased, porphyry strain around. Highlands heat magma caused by the heat, resulting in a long-term groundwater and hydrothermal convective circulation and water - rock interaction, led to the mineralizing fluid along the fault zone on both sides of wall rock in particular, is on the plate surrounding rock the fine fissures form veinlets ~ disseminated like molybdenum mineralization; due to fluid pressure fluctuations, so that the surrounding rock repeatedly rupture or Zhang He, ore-bearing hydrothermal pulsating precipitation bearing quartz stockwork intertwined. 8 symbols for prospecting Prospecting Prediction: potassium silicide, silicide, zeolite, red mud of pyritization and peacocks petrochemical. Potassium silicide, fine stockwork more intensive development, and the deeper more single pulse width and pulse color, the more favorable mineralization; alteration zone of the brick red Zeolitization development; favor red mud dykes of superposition parts the mineralization; scattered disseminated, film, pyrite and peacock petrochemical; favorable combination of ore-forming elements of Mo, Cu, Ag, As. Prospecting Prediction: mine prospecting emphasis should be placed on the exploration line NEE to deep; Spa rock body focus found 42 molybdenum mineralization geological evaluation, the other to focus on research F ₃₂ F ₁₆ and F _{intersection at 20}; molybdenum mine in the area looking for, should be concerned about the Indosinian granite body adjacent to deep faults and Precambrian basement ( pulse) outcrop.}}}}}}}}}

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